I found out recently my IP had been blacklisted and thus I couldn't send any emails. On the CBL site it says...
"IMPORTANT: Many CBL/XBL listings are caused by a vulnerability in Mikrotik routers. If you have a Mikrotik router, please check out the Mikrotik blog on this subject and follow the instructions before attempting to remove your CBL listing."
I have a MikroTik router, so I wondered how do they know? Is this information contained in any packets of data sent to and from a server when sending an email and the IP was blacklisted preemptively or has someone hacked my router and done something to get me blacklisted?
FWIW, this is more of a hypothetical question than a 'what I did' one, but FYI I wasn't doing anything blacklist worthy like running a mail server for example. Just normal every day use of a normal PC connected to a home network.
The question is simply when sending an email is there anything in that process that passes on the details (i.e. model and firmware version) of your router?